Trailer unit



Jan. 27, 1942. G. K. MULHOLLAND, 2,271,304

TRAILER burr 1 Fil ed Jan. ,8, 1940' s Sheets-Sheet 1 INVENTOR Jam 1942- G.'K. M ULiHOLLA ND 71,304

TRAILER UNI T Filed Jan. "8, 1940 s Sheets-Sheet 2' v INVENTOR ATTORNEY Jan. 27, 1942. G. K. MULHOLLAND 2,271,304

I TRAILER UNIT j v Filed Jan. 8; 1940 I 3 Sheets-Sheet s 3 pendenijllysprung.v :m 7;-

Another object is to provide a.;trailing unit of simple, practical,,gand inexpensive construction Patented Jan. 211942 i a V A v I I 'v j I a umen,m l onmgw 5; 7

r This inventionirelates to .vehicleconstructlori] and more particularly to a construction for a caster unit forming part 'of a trailer'adapted to be connected to and drawn by a power,vehicie.='

. One of the primecbj'ectsof'the invention'is-to design a. multiple wheeled V structed and arranged that. each wheel is ind'ewhich can be easily and quickly attached-or dew mew 8; w. ahmrsi im r mgiihs. (CKIHQF l caster unit, so; .con- .f

tached, andwhich is economical tofmanufacture and assemble, v

A further'object to provide a; trailer construction including a i swiveled. ,caster. wl'ieel v mounting which will not, twist or bind, and in which either wheel is freeitoraise or lower V relation to its companionwheelg;

A still further. object is to provide sterner.

unit. includingv multiple .1 wheels arranged; to caster .about a common stem so that one wheel may ride over a raised obstacle, or drop into a depression without binding or twisting the wheel assembly, and in which, each wheel will carryits v proportionate load at all times.

A further object still is todesign a' trailer havl-f' l3, which men'- mcuntedonfwheels'lq as' usual. The forward endoffthe frameis iormed with a ing a swiveled caster wheel.support,softhatit;

backsu p, turns asaunit-with' the yehicl'e; t'o' which it'is attached, andin fact operates as; an integral extension of thejpower vehicle.

Other objects are also-comprehendedby lmy invention, all oi which togetherwith the precise nature of my improvements, will be readily apparent when the following description and claims are considered with reference totheaccompany- 011, I: n 'In the drawings:

improved caster unit. 7 r r n Fig. 2 is atop plan view, the attaching-bracket ing drawings which forrn partioi 'the specifica being broken away to more clearly how the con- H struction. n o A Fig. 31s a rear elevational view,-I theibroken lines showing one of the wheels raised for passing over an obstacle. n e I Fig. 4 is afragmentary vertical sectional view showing the stem, bracket; andhub mounting. Fig. 5 i's'a side elevational view showing a three-point suspensiontrailer unit. a

.s emlqh-cq lo r V jtorticnal'twist andtbinding-p -thelhub and; assoi d' s-9 mm? und ei be l c di i al av el m n t d. m imiitove rc n mt n as w l b h r inatter Y m ea u n e r -9.. 1 Referring-now m0 1 kickup; [5, and the s :Atrailertong e. l6jis this hem at'the I af-suitable I all and socket or bracket i8;

muchas these wheels aredisposed'in a -plane on oiiD0site'sid-S.O th vertical'cemer-of-the lamb tends. to 'bindand impose a.

mg: m which .1

tional frame is mounted thereonas usual the. rear end being resiliently supported gon springs I! from. an axle cured thereto insany.approvedv rnanner. ,7

' trailer-hitch (not Q shownffor attaching to a power vehiclei in 'tlie h conventional manner, .Y. 7

mov ic i il an e The caster unit I a centrally 'disDQsed hub is having formed'integral therewith in whicha yertically M is os S s", -mo t d a dlsec e *PY means 01 i h r .1-; Onehi z 2 nm yided in the-bracketfianges shown to -:faci1i H itat' mounting andsecuring the bracket-to the kick-up frame;

A hubmemberzi is revolvably mountedionthe stern ill and includes anti-friction.. bearing assembliesll andfl respectivelyj Abearingseal or. cap. "26' being mounted on theigcone 11 which v forms the; inner shell orthe bearing raceway,, and the upper; end of hub. is shouldered as'at,=;28-

{so that a'reasonablyclosejoint ia provided. The lower end of thehub 23 is bored as at 29" andaccommodates. the bearingfassembly 25 the Fig. 6 is a side elevational view showing a modiconnection lower end of the 'stem'beingthreadedlto receive i a flanged nut" so that the hub-is securely held in-iposition, set screwsjl being. mounted/in the flange of this nut andpermit adjustment totake up bearing wear andadjustmentetc. A centrally disposed chamber 32 isprovided in the hub 23 and serves asa grease'reservoir into which lubrl cant is'introduced through the fitting 33. a

.e: a ticul fih ar have myinnpfcved cone 7. 1 struction; The numeralil ll.indicatesthe conven- V or v th ee-Po n sus en ipnl trailer- This is preferably fabricated. from structural shapes. properly welded together anda body u.

wiveled -caster unit'qis se-i Z r .7

A forwardly projecting arm 34 is cast integral withthe hub 23 and terminates in a transversely disposed bearing 35 as shown, said bearing being bored to accommodate the bolt 36 and by means of which the rearwardly projecting wheel bearing members 31 are pivotally secured thereto, the opposite ends of said wheel bearing members terminating in an extension hub 38 on which a wheel assembly 39 is revolvably mounted in .any approved manner.

Internally threaded spring seats 40 are cast integral with the hub 23, and similar seats 4| are provided on the wheel bearing member as shown,

From the foregoing description it will be obvious that I have perfected a very simple, practical, and economical trailer caster unit construction in which each wheel is individually sprung, which accommodates itself to the contour of the roadway over which the vehicle travels without binding or strain on the associated parts; which travels accurately and true at high speeds; andin which the load is evenly distributed at all times. i

What I claim is:

'1. A trailer unit having a frame adapted to be connected to a vehicle, a multi-wheeled caster coil springs 42 being mounted in these .seats, and

bumpers 43 and 44 respectively are provided in the respective spring seats 40 and 4|, and these i can be formed of rubberor other resilient material to eliminate sharp hammer blows when traveling over' uneven roadways when the trailer is loaded beyond the capacity of the springs 42. The fact that each wheel is independently sprung eliminates any possibility of binding when one wheel drops into a rut or rides over an obstacle,

and it further insures each wheel carrying its proper proportionate share of the total load.

I wish to direct attention'to the fact that the hub is freely revolvable about the stem 20 and the pivotal connection of the wheel bearing members3l to theend of the'arrn 34' permits the structure to raise and lower with relation to the ground engaging wheel as the'spring is flexed.

In Figs. 6 and7 of the drawings I have shown a slightly modified construction; a downwardly projecting arm 45 being cast integral with the hub 23 and terminates in a bearing 46 as usual, a bearing 41 is cast integral with each of the wheel bearing members 31 at a point intermediate its length,

and a bolt 48 serves to pivotally secure these wheel bearing members to the bearing 46 which forms a part of the hub. V f

A laterally projecting arm- 49 is cast integral with the hub'23 and terminates in a bearing 50, and a horizon-tally disposed bolt 5| is mounted in said bearingindividual rods 52'are mounted on said bolts, the upper ends of each rod being formed with a bearing '53, which is revolvably mounted on the bolt 5| and nuts 54 serve to secure the members in assembled relation.

The wheel bearing members 31 project beyond the bearings 41 as shown, and an opening 55 is provided in the outer end of each member and through which the rod members 52 extend, the

lower end of each rod being shouldered as at 56,

and an externally threaded spring cup 51 is mounted thereon, the end of the rod being threaded to receive a nut 58 as usual.

A similar spring cup 59 is provided adjacent the end of the wheel bearing member 31 and a spring 50 is interposedbetween and threaded on the spring cups, so that when the wheel passes over a raised obstacle in the roadway the spring will becompressed accordingly. Each assembly is identical and each wheel is independently sprung.

unit including a stem connected to said frame, a hub revolvable on said stem, and individual independently sprungwheel bearing members pivotally connected to said hub about a common center to'permit each wheel to raise and lower with relation to andwithout affecting the companion 20 wheel.

2. A trailer unit having a frame adapted to be connected to a vehicle and including a bracket, a

vertically disposed stem mounted therein, a hub revolvably mounted on said stem, individual individually sprung wheel bearing members pivotally connected to said hub, to permit each wheel bearing member to raise andlower with relation to andwithout afiecting the companion wheel bearing member.

'3. A trailer unit adapted to be connected to a vehicle and including a multi-wheeled caster unit comprising a bracket, a stem connected to said bracket, a hub revolvably mounted on said stem and havingan outwardly projecting arm formed integral therewith, rearwa-rdly extending wheel bearing members pivotally connected to said arm about a common center, each member being provided with a groundengaging' wheel on the free endthereof, and an independent spring interposed between each wheel bearing member and the hub. 1 w

4. A trailer unit adapted to be'connected to a vehicle and including a multi-wheeled caster unit comprising averticallydisposed stem, a hub revolvably mounted on said stem and provided with an outwardly projecting arm, closely spaced individual wheel bearing members pivotally secured to said arm and provided with ground engaging wheels on the free'ends thereof, spring seats on the hub and wheel bearing members respectively, and springs mounted in said spring seats.

5. A" trailer unit adapted to be connected to a vehicle and including a multi-wheeled caster unit comprising a bracket, a vertically disposed stem, a hub revolvably mounted thereon, independent wheel bearing members pivotally connected to said hub, 'and resilient means associated with said hub and with each wheel bearing member for independently springing each of said members 'to permit each wheel bearing member to raise and lower without affecting the companion r'rlemberi I V GEORGE K. MULHOLLAND. 

